Medals

6 Takedowns

12 Takedowns

20 Takedowns

Performing 50 takedowns as Batman earns the player the Eternal trophy/Achievement.

Tips

Batman, Batgirl and Azrael are likely the best options if you're grinding challenge maps for extra Waynetech points. While Batman needs to be upgraded in story mode to be effective, Batgirl and Azrael play similarly to him. As both Batman and Azrael need fear takedown charges to perform double takedowns, Batgirl has the added benefit of being able to perform an unlimited amount of them.

Smoke bombs are your friend in this challenge, as no enemy can see through the smoke cloud, allowing easy takedowns. They also regenerate in this challenge.

Mines planted by enemies are difficult to deal with most characters, as the floor may be covered with them after a while. As Batman has the Disruptor that can destroy both ground and vantage point-based mines, he suffers from them far less than the other characters. The disruptor also regenerates ammunition in this challenge.

Inverted takedowns are an excellent way of taking enemies down, as they map has 16 vantage points, which the enemies regularly clean by shooting the ropes of your past victims.

Trivia

Due to the removal of Extreme Challenges, this is the only Challenge Map in Knight to share it's location with another challenge, in this case Terminal Velocity.

Enemies taken out with Red Hood's handguns count as takedowns, but won't add extra time. This was done to prevent spamming the gadget. Ranged beatdowns still add time, however.

It's entirely possible that Red Hood's guns were the reason a time limit was added, as otherwise the player could just swing between vantage points and take down the enemies with ease. Adding a time limit makes this harder, and is preferable over nerfing the character/gadget.